JP2550741B2 - Slide table mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a table supported on a bed, the screw shaft being attached to the bed and the screw shaft being attached to the table by the relative rotation of the screw shaft. The present invention relates to a slide table mechanism that is advanced and retracted by a nut that relatively moves along the guide table and guides the advance and retreat by a roller with a cage between a bed and a table.

[Conventional technology]

A conventional slide table mechanism includes a table supported on a bed, for example, a ball screw, that is, a screw shaft that is pivotally supported by the bed to rotate, and a ball screw nut that is fixed to the table and moves forward and backward by the rotation of the screw shaft. The caged roller configured to be advanced and retracted by means of the above-mentioned method uses a cylindrical roller whose length dimension is significantly larger than its diameter.

[Problems to be Solved by the Invention]

However, according to the conventional technique, due to the eccentricity of the screw shaft or the ball screw nut, the ball screw nut itself is shaken during the movement of the ball screw nut, and this is directly transmitted to the table. There is a problem that the smoothness of the movement of the table is hindered, such as the occurrence of vibration. In order to solve this problem, the ball screw nut and the table are not fixed but a static pressure bearing is interposed between them to smoothly move the table. The use of the bearing has a problem that the structure becomes complicated and the cost becomes high.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a slide table mechanism having a simple structure and capable of ensuring smooth movement of the table.

[Means for solving the problem]

The slide table mechanism of the present invention includes a bed, a table which is guided and supported between the bed by a roller with a cage so as to be movable back and forth, a screw shaft attached to the bed, and the screw shaft attached to the table. In a slide table mechanism including a nut that relatively moves along a screw axis by relative rotation of the table, the table and the bed are relatively movable in the axial direction of the screw axis between the table and the bed. A vertical urging means for guiding and urging the both in the vertical direction to approach each other is provided, and a leaf spring is interposed between the table and the nut, and the leaf spring is formed on the nut. It is formed integrally with the nut by splitting, and is opposed at symmetrical positions with the screw shaft sandwiched therebetween, and is parallel to the screw shaft and parallel to the vertical direction. It is configured to have a surface composed.

It is preferable that the diameter and the length of the caged roller are substantially equal to each other, and it is also preferable that the leaf spring is constituted by an outer portion of a slit formed in parallel with the left and right surfaces of the nut.

Further, in the roller with cage, the rollers form a plurality of rows with respect to the cage, and the plurality of rows of rollers are arranged such that the position of each roller in one row in the row direction is the other row between adjacent rows of rollers. It is preferable that the rollers are positioned between the rollers and the tracks of the rollers in the adjacent rows are partially overlapped with each other so that the rollers are arranged in a zigzag pattern.

[Action]

According to this invention, since the leaf spring is interposed between the table and the nut, the nut and the table are integrated in the axial direction of the screw shaft, and the displacement of the nut in the left-right direction is caused by the deformation of the leaf spring. It is absorbed and not transmitted to the table. Further, if the leaf spring is constituted by an outer portion of a slit formed on the nut, the leaf spring and the nut can be easily assembled as one unit, while the leaf spring and the nut are united with each other, the nut is liable to be vibrated or the like. On the other hand, there is no risk that the leaf spring will come loose.

Further, even when a force that separates the table in the up-down direction from the bed acts due to a slight deformation of the screw shaft and the nut that rotate relative to each other, the up-down direction biasing means
Since the table is biased toward the bed, it is possible to prevent the table from being lifted, so that the table can be moved forward and backward with high accuracy.

Furthermore, if the diameter of the roller with cage is approximately equal to the length, skew will not occur because the length will be shorter than the diameter, and if the leaf spring is composed of the outer part of the slit, the leaf spring and nut And become one.

Furthermore, when the rollers with cages are arranged in the zigzag pattern, the orbits of the rollers in adjacent rows partially overlap each other, so that the orbital surfaces do not wear with a width equal to the length of the rollers and the widthwise direction is reduced. It will wear on average.

〔Example〕

FIG. 1 is a sectional view of the slide table mechanism, and FIG.
The figure is a plan view in which a part of FIG. 1 is omitted. The structure is such that a table 2 for mounting a machine tool (not shown) is mounted on the upper surface of the bed 1, and The supported screw shaft 3 is screwed to a ball screw nut 4 fixed to the lower surface of the table 2 via a ball (not shown). Instead of the ball screw nut 4, it is possible to use a nut that does not use a ball.

The screw shaft 3 is rotatably supported on the bed 1 via a bearing 5 fitted on one end and a bracket 6 fixed to the bearing 5, and the other end (not shown) is provided for rotating the screw shaft 3 in the forward and reverse directions. A motor and a speed reducer are connected if necessary,
The middle part is also rotatably supported on the bed 1 by the same means as the bearing 5 and the bracket 6.

The ball screw nut 4 is bolted to the table 2 at the left and right ends that are far from the screw shaft 3 (the bolt holes 4a are shown in FIG. 2), and the left and right outer surfaces are vertical lines and the screw shaft. It forms a plane including a line parallel to 3. The ball screw nut 4 is provided with a slit 7 from the upper surface along the left and right outer surfaces, and a leaf spring 8 is formed by a thin portion between the slit 7 and the left and right outer surfaces. The leaf spring 8 has a flat plate shape including a vertical line and a parallel line to the screw shaft 3, and the ball screw nut 4 is fixed to the table 2 via the leaf spring 8. A gap is provided between the ball screw nut 4 and the table 2 on the upper surface of the central portion in the width direction, as shown in FIG.

Bed-side race plates 11 and 12 which substantially form a part of the bed 1 are bolted to the left and right sides of the screw shaft 3, and the left and right sides of the ball screw nut 4 are attached to the lower surface of the table 2. The table-side race plates 13 and 14 that substantially form a part of the table 2 are fixed by bolts, and the facing surfaces of the facing race plates 11 and 13 form a planar raceway surface 15, and the facing race plates 12 are also facing each other. , 14 form a raceway surface 16 having a V-shaped cross section. A roller 17 with a cage is provided on the plane raceway 15 and the V-shaped section raceway 16.
To support the load of the table 2 itself and the load of the equipment mounted on the table 2 on the bed 1,
In addition, the table 2 can be moved with respect to the bed 1.

The cage-equipped roller 17 has the same diameter and the same length as or close to it, and is assembled in two rows in the cage 18 so that the two rollers can support the load of one conventional roller. I am configuring. In FIG. 2, two sets of rollers with cages 17 are arranged in series on one end side of the planar raceway surface 15, but also on the other end side (not shown) of the planar raceway surface 15 in series. Spacers 19 for maintaining the distance between the caged rollers 17 on both ends are interposed between these two ends. However, it is a matter of course that a plurality of the cages 18 of the caged roller 17 in series may be integrally formed into one cage 18 in the longitudinal direction of the planar raceway surface 15.

The cage-equipped roller 17 is arranged on two slopes having a V-shaped cross section on the V-shaped section raceway surface 16, and the cage-shaped roller 17 is arranged in the plane-shaped raceway surface 15 in the longitudinal direction of the V-section section raceway surface 16. It is the same as the one. Also with this caged roller 17, each cage 18 can be integrated like the caged roller 17 of the planar raceway surface 15.

Further, the caged roller 17 having the planar raceway surface 15 and the V-shaped section raceway surface 16 does not use the spacer 19
Of course, it is also possible to use the caged roller 17 in which the cage 18 is continuous in the direction along the respective raceway surfaces 15 and 16 and is integral therewith.

As is known, the lower surface of the table 2 has an L-shaped member 21 in cross section.
Are fixed by bolts (bolt hole 21 in FIG. 2).
a is shown), between the upper surface on the lower side and the lower surfaces of the holding members 11a, 12a arranged on the lower side of the bed side race plates 11, 12 and the rolling elements 11b, 12b and the holding members from above. 11a, 12a
And the springs 22 and 22 are respectively interposed. On the right side of the screw shaft 3 in FIG. 1, the holding member 12a, the transfer member 12b and the spring 22 interposed between the lower upper surface of the L-shaped member 21 and the lower surface of the bed side race plate 12 cause the upper and lower parts on the right side. A direction biasing means is configured, and similarly, on the left side of the screw shaft 3, the holding member 11 is interposed between the lower upper surface of the L-shaped member 21 and the lower surface of the bed side race plate 11.
a, the rolling element 11b and the spring 22 constitute a vertical urging means on the left side, and these vertical urging means can relatively move the table 2 and the bed 1 in the axial direction of the screw shaft 3. And vertically urging means for urging the two in a direction in which they approach each other in the vertical direction.

Then, the screw shaft 3 is rotated by the rotation of a motor (not shown) to move the ball screw nut 4 in the axial direction of the screw shaft 3, and the table 2 is moved integrally with the movement of the ball screw nut 4. It At this time, even if the screw shaft 3 and the ball screw nut 4 are slightly deformed and the ball screw nut 4 is shaken or vibrated when the ball screw nut 4 is moved, the leaf spring 8 is deformed. Since this is absorbed, the shake and vibration are not transmitted to the table 2.

Further, since the roller length of the caged roller 17 is the same as or close to the diameter, no skew occurs when the table 2 is moved, and the rollers are arranged in a plurality of rows, so that individual rollers are provided. Even if the length of the roller is short as described above, the load can be sufficiently supported.

Thus, since the table 2 does not transmit the vibration from the ball screw nut 4 and the cage roller 17 does not generate a skew, the table 2 can be smoothly moved.

The amount of displacement of the table 2 in the left-right direction at this time is shown in FIG. 6. Not only does the displacement hardly exist when the table 2 moves forward, when stopped, and when it moves backward, but also when it moves forward. There is almost no displacement between when retreating. On the other hand, FIG. 7 shows the displacement amount in the conventional example. This is because not only the displacements at the time of forward movement and backward movement are large, but the displacement amount between forward movement and backward movement is Understand that it is extremely large.

The number of rows of the cage-equipped rollers 17 is arbitrarily set according to the load of the table 2 and the equipment mounted on the table 2. In the example of FIGS. 3 and 4, the number of rows is three. Further, in the example of FIG. 5, the rollers 17 are staggered, that is, the rollers in three rows.
17 rows are positioned between adjacent roller rows such that the rollers 17 of one row are positioned in the row direction between the rollers 17 of the other row, and the tracks of the rollers 17 of each adjacent row are aligned. It is configured to overlap in the section. W in the figure is the overlapping portion of the tracks. As a result, the orbits of the rollers 17 in each row are not formed separately, and the planar orbital surface 15 and the V-shaped cross-sectionally orbital surface 16 are worn on average, resulting in high durability.

〔The invention's effect〕

As described above, according to the present invention, since the plate spring is interposed between the table and the nut, the nut and the table are integrated in the direction of the screw shaft, and the displacement of the nut in the left-right direction does not occur. It is absorbed by the deformation of the leaf spring and is not transmitted to the table. Further, since the leaf spring is constituted by the outer portion of the slit formed on the nut, the leaf spring can be easily formed by known electric discharge machining or cutting as a machining means, while the leaf spring and the nut are Not only is it easy to assemble the slide table mechanism, but there is no fear that the leaf spring will come loose with respect to the nut due to vibration or the like.

Further, even when a force that separates the table in the up-down direction from the bed acts due to a slight deformation of the screw shaft and the nut that rotate relative to each other, the up-down direction biasing means
Since the table is biased toward the bed while allowing relative movement between the bed and the table, it is possible to prevent the table from being lifted up, so that there is also an effect that the table can be moved forward and backward with high precision. .

Furthermore, if the diameter of the roller with cage and the length are substantially equal, there is an effect that the skew is not generated because the length becomes shorter with respect to the diameter. Furthermore, if the rollers with cage are arranged in the zigzag pattern, Since the orbits of the rollers in adjacent rows partially overlap, the orbital surfaces do not wear with a width equal to the length of the rollers, and they wear on average in the width direction, eliminating uneven wear. There is also.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment, FIG. 2 is a plan view showing a state in which a table and a table side race plate of FIG. 1 are removed, and FIG. 3 is a plan view showing a second example of a roller with a cage. Fourth
FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, FIG. 5 is a plan view showing a third example of the roller with cage, FIG. 6 is an explanatory view showing the amount of displacement of the table of the embodiment, and FIG. It is explanatory drawing which shows the displacement amount of the table of a prior art example. 1 ... Bed, 2 ... Table, 3 ... Screw shaft, 4 ...
Ball screw nut, 7: slot, 8: leaf spring, 11
a, 12a …… Retaining member, 22 …… Spring, 17 …… Roller with cage.

Claims (4)

(57) [Claims] 1. A bed, a table which is guided and supported by a roller with a cage so as to be movable back and forth between the bed, a screw shaft attached to the bed, and a relative rotation of the screw shaft attached to the table. A slide table mechanism provided with a nut that relatively moves along the screw axis by means of guiding the table and the bed so as to be relatively movable in the axial direction of the screw axis between the table and the bed. A vertically urging means for urging both of them in a vertically approaching direction is provided, and a leaf spring is interposed between the table and the nut, and the leaf spring is a nut formed by a slit formed in the nut. Are formed integrally with each other, and are opposed to each other at symmetrical positions with the screw shaft interposed therebetween,
A slide table mechanism having a plane parallel to the screw axis and parallel to the vertical direction. 2. The slide table mechanism according to claim 1, wherein the rollers with cages have substantially the same diameter and length. 3. The slide table mechanism according to claim 1, wherein the leaf spring is constituted by an outer portion of a slot formed in parallel with the left and right surfaces of the nut. 4. The caged roller comprises a plurality of rows of rollers with respect to the cage, and the plurality of rows of rollers are arranged in the row direction of each roller of one row between adjacent rows of rollers. 2. The roller is positioned between the rollers of the other row, and the orbits of the rollers of the adjacent rows are partially overlapped, so that the rollers are arranged in a staggered pattern.
The slide table mechanism according to claim 3.